An Li, Hong Sungtak, Turon Tara, Pavletic Adriana, Johnson Christopher S, Derbyshire John A, Shen Jun
National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA.
Magn Reson Med. 2025 Jul;94(1):4-14. doi: 10.1002/mrm.30423. Epub 2025 Jan 9.
Two-shot γ-aminobutyric acid (GABA) difference editing techniques have been used widely to detect the GABA H4 resonance at 3.01 ppm. Here, we introduce a single-shot method for detecting the full GABA H2 resonance signal, which avoids contamination from the coedited M macromolecules.
Density matrix simulation was conducted to optimize the pulse-sequence timing, aiming to reduce the interfering glutamate H4 signal and minimize the correlation between glutamate and GABA arising from spectral overlap. The optimized sequence was used to acquire MR spectroscopy data from a 14-mL voxel in the anterior cingulate cortex of 6 healthy participants. H-MRS experiments following the oral administration of [U-C]glucose were also conducted.
The GABA H2 peak was consistently observed in all participants. The GABA/creatine ratios in the participants were determined to be 0.07 ± 0.01 with Cramer-Rao lower bounds of 8.0% ± 2.2%. Spectra acquired following [U-C]glucose intake demonstrated the feasibility of using GABA H2 as a highly sensitive reporter for GABA C2.
The proposed single-shot GABA editing method effectively minimizes interference from the glutamate H4 signal in the detection of the full GABA H2 signal, which resonates at a spectral region with much reduced macromolecule contamination.
双激发γ-氨基丁酸（GABA）差异编辑技术已被广泛用于检测3.01 ppm处的GABA H4共振。在此，我们介绍一种用于检测完整GABA H2共振信号的单激发方法，该方法可避免来自共编辑的M大分子的污染。
进行密度矩阵模拟以优化脉冲序列定时，旨在减少干扰性谷氨酸H4信号，并最小化因光谱重叠而产生的谷氨酸与GABA之间的相关性。使用优化后的序列从6名健康参与者前扣带回皮质的一个14 mL体素中获取磁共振波谱数据。还进行了口服[U-C]葡萄糖后的氢磁共振波谱（H-MRS）实验。
在所有参与者中均一致观察到GABA H2峰。参与者的GABA/肌酸比率确定为0.07±0.01，克莱姆-拉奥下界为8.0%±2.2%。摄入[U-C]葡萄糖后获取的波谱证明了将GABA H2用作GABA C2高灵敏度报告物的可行性。
所提出的单激发GABA编辑方法在检测完整GABA H2信号时有效最小化了谷氨酸H4信号的干扰，该信号在一个大分子污染大大减少的光谱区域共振。
